I speculate that the energy behind these posts comes from deeply wanting to believe that sex outside marriage has no negative consequences and is not wrong, just as Ms. Filipovic wants to believe that abortion has no negative consequences and is not wrong.
I don't know how you're arriving at that speculation. (Bear with me here, I may have misunderstood you.) Are you saying this because they condemn abortion but not nonmarital sex? I think the FReepers to whom you refer, would condemn nonmarital sex as well.
How many men are condemned for the abortion of their prenatal sons and daughters? Not many. Yet there are as many men involved in this, as women --- simply because they have sired children under circumstances that expose them to high risk, and then through weakness or indifference --- if not emotional pressure or worse --- consented to their deaths.